In recent years, a need has arisen for high-performance polymeric materials in the development of electronic devices such as liquid-crystal displays, organic electroluminescent (EL) displays, touch panels, optical semiconductor (LED) devices, solid-state image sensors, organic thin-film solar cells, dye-sensitized solar cells and organic thin-film transistors (TFT).
The specific properties desired of such materials include: (1) heat resistance, (2) transparency, (3) high refractive index, (4) high solubility, (5) low volume shrinkage, (6) high moisture resistance at high temperatures, and (7) high film hardness.
The inventor and others earlier discovered that polymers containing recurring units which have a triazine ring and an aromatic ring possess a high refractive index and are able, with the polymer alone, to achieve a high heat resistance, high transparency, high refractive index, high solubility and low volume shrinkage, thus making such polymers suitable as film-forming compositions in the fabrication of electronic devices (Patent Document 1).
In regards to the production of spacers, insulating films, protective films and the like in liquid-crystal display elements, thin-film formation is carried out by coating methods using compositions of a high-refractive-index material dissolved in an organic solvent.
An ink-jet coater is sometimes employed at the time because patterned coating only on desired regions is possible with such a coater.
The head of this ink-jet coater tends to be attacked by organic solvents, and so there are limitations on the solvents that may be used in preparing the composition. Also, given the necessity during coating for the composition to be ejected from the head as tiny droplets, there are also limitations in terms of the viscosity and surface tension of the composition.